The purpose of this study is to determine the effects of Simvastatin (Zocor), a potent inhibitor of cholesterol synthesis and an extremely effective drug to lower low density lipoprotein (LDL) cholesterol, on the levels of blood fat and cholesterol-containing packages (chylomicrons and chylomicron remnants) after individuals eat a meal containing fat and cholesterol. Recent studies have shown that the levels of fat in the blood after a meal can indicate someone's risk for having coronary artery disease. Although Simvastatin and other drugs like it very effectively lower LDL cholesterol, much less is known about their ability to lower the levels of blood fat and cholesterol after a meal. This study will compare an FDA-approved dose of Simvastatin (20mg/day) with a higher than approved dose (80mg/day) to a placebo.